Exhaust driven turbochargers are included in internal combustion engines to increase the power output to weight ratio of the engine. Turbines in the turbochargers may experience high temperature conditions. Consequently, the turbine may be cooled via an engine cooling system branch which is coupled to the engine's radiator. Additionally, the turbine may be constructed out of materials that are less susceptible to the high temperature exhaust system conditions. However, material which can withstand the high temperature conditions may be costly. Furthermore, during other operating conditions the turbine and the engine may have different cooling requirements. Thus, the turbine and/or the engine may be provided with insufficient cooling or warming during certain periods of engine operation.
In one approach, a method for operating an engine system in an internal combustion engine comprising during a first operating condition, circulating coolant through a coolant jacket in a turbine housing at least partially enclosing a turbine rotor and during a second operating condition, replacing coolant in the coolant jacket with air from a venting reservoir. In this way, the turbine may be cooled via a liquid cooling system during certain operating conditions and filled with air during other operating conditions to enable exhaust system components to heat up more quickly as a result. The turbine may be selectively cooled to improve engine operation during a cold start as well as a period of engine operation when the engine has warmed up.